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Friedrich Wilhelm Argelander
Friedrich Wilhelm August Argelander (22 March 1799 – 17 February 1875) was a German astronomer. He is known for his determinations of stellar brightnesses, positions, and distances. Life and work Argelander was born in Memel in the Kingdom of Prussia (now Klaipėda in Lithuania), the son of a father of Finnish descent, Johann Gottlieb Argelander, and German (Prussian) mother, Dorothea Wilhelmina Grünlingen. He studied with Friedrich Bessel, whose assistant he became in 1820, and obtained his Ph.D. in 1822 at University of Königsberg. From 1823 until 1837, Argelander was the head of the Finnish observatory, first in Turku and then in Helsinki. He then moved to Bonn, Germany. There he designed and built a new observatory at the University of Bonn with funding approved directly by King Frederick William IV whom Argelander had become friends with in his childhood. This lifelong friendship had started when the then crown prince temporarily lived in Argelander's parents hou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Klaipėda
Klaipėda (; ; german: Memel; pl, Kłajpeda; russian: Клайпеда; sgs, Klaipieda) is a city in Lithuania on the Baltic Sea coast. The capital of the eponymous county, it is the third largest city and the only major seaport in Lithuania. The city has a complex recorded history, partially due to the combined regional importance of the usually ice-free Port of Klaipėda at the mouth of the river . Located in the region of Lithuania Minor, at various times, it was a part of the Polish–Lithuanian Commonwealth, Prussia and Germany until the 1919 Treaty of Versailles. As a result of the 1923 Klaipėda Revolt it was annexed by Lithuania and has remained with Lithuania to this day, except between 1939 and 1945 when it was occupied by Germany following the 1939 German ultimatum to Lithuania. The population has migrated from the city to its suburbs and hinterland. The number of inhabitants of Klaipėda city shrank from 202,929 in 1989 to 162,360 in 2011, but the urban zone o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Observatory
An observatory is a location used for observing terrestrial, marine, or celestial events. Astronomy, climatology/meteorology, geophysical, oceanography and volcanology are examples of disciplines for which observatories have been constructed. Historically, observatories were as simple as containing an astronomical sextant (for measuring the distance between stars) or Stonehenge (which has some alignments on astronomical phenomena). Astronomical observatories Astronomical observatories are mainly divided into four categories: space-based, airborne, ground-based, and underground-based. Ground-based observatories Ground-based observatories, located on the surface of Earth, are used to make observations in the radio and visible light portions of the electromagnetic spectrum. Most optical telescopes are housed within a dome or similar structure, to protect the delicate instruments from the elements. Telescope domes have a slit or other opening in the roof that can be opened du ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eduard Schönfeld
Eduard Schönfeld (22 December 18281 May 1891) was a German astronomer. Education Schönfeld was born at Hildburghausen, in the Duchy of Saxe-Meiningen, where he had a distinguished career at the gymnasium. On leaving the gymnasium, he desired to devote himself to astronomy, but abandoned the idea in deference to his father's wishes. He went first to Hanover, and afterwards to Kassel to study architecture, for which he seems to have had little inclination. 1849 found him studying chemistry under Bunsen at Marburg, where his love for astronomy was revived by Gerling's lectures. In 1851 he visited the Bonn Observatory and studied astronomy under Friedrich Wilhelm Argelander. In 1853 he was appointed assistant, and in the following year won a doctor's degree with his treatise ''Nova elementa Thetidis''. At Bonn he took an important part in preparing the ''Durchmusterung'' of the northern heavens. He took up the investigation of the light-changes in variable stars, devoting to this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adalbert Krüger
Karl Nikolaus Adalbert Krueger (9 December 1832 – 21 April 1896) was a German astronomer. Born in Marienburg, Prussia (now Malbork, Poland), he was editor of '' Astronomische Nachrichten ''from 1881 until his death. Krueger died of a heart condition in Kiel at the age of 63. Life and work In 1851, Krueger entered the University of Berlin where he studied mathematics and science. In 1853, showing a special preference for astronomical studies, Krueger moved to the University of Bonn and became an assistant to the astronomer Friedrich Wilhelm Argelander at the Bonn Observatory. Under Argelander's supervision he produced data for the comprehensive astrometric star catalogue known as the Bonner Durchmusterung, together with fellow student Eduard Schönfeld . Starting in Bonn, he undertook a lifelong study of the orbit of the minor planet Themis, whose perturbations by Jupiter eventually enabled him in 1873 (while at Helsinki Observatory) to determine the mass of the latter pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proper Motion
Proper motion is the astrometric measure of the observed changes in the apparent places of stars or other celestial objects in the sky, as seen from the center of mass of the Solar System, compared to the abstract background of the more distant stars. The components for proper motion in the equatorial coordinate system (of a given epoch, often J2000.0) are given in the direction of right ascension (''μ''α) and of declination (''μ''δ). Their combined value is computed as the ''total proper motion'' (''μ''). It has dimensions of angle per time, typically arcseconds per year or milliarcseconds per year. Knowledge of the proper motion, distance, and radial velocity allows calculations of an object's motion from our star system's frame of reference and its motion from the galactic frame of reference – that is motion in respect to the Sun, and by coordinate transformation, that in respect to the Milky Way. Introduction Over the course of centuries, stars appear to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Groombridge 1830
Groombridge 1830 (also known as 1830 Groombridge or Argelander's Star)Peters, C. A. F.; "On the Parallax of Argelander's Star", Monthly Notices of the Royal Astronomical Society, December 1853, v.50, p.302, is a star in the constellation Ursa Major. Description It is a yellow-hued class G8 subdwarf catalogued by British astronomer Stephen Groombridge with the Groombridge Transit Circle between 1806 and the 1830s and published posthumously in his star catalog, ''Catalogue of Circumpolar Stars'' (1838). Its high proper motion was noted by Friedrich Wilhelm Argelander in 1842. It is from the Sun as measured by the Gaia spacecraft, which, as the distance is nearly 10 parsecs, means its absolute magnitude is almost equal to its apparent magnitude. It is a member of the galactic halo; such stars account for only 0.1 to 0.2 percent of the stars near the Sun. Like most halo stars, it has a low abundance of elements other than hydrogen and helium—what astronomers term a m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variable Star
A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as either: * Intrinsic variables, whose luminosity actually changes; for example, because the star periodically swells and shrinks. * Extrinsic variables, whose apparent changes in brightness are due to changes in the amount of their light that can reach Earth; for example, because the star has an orbiting companion that sometimes eclipses it. Many, possibly most, stars have at least some variation in luminosity: the energy output of the Sun, for example, varies by about 0.1% over an 11-year solar cycle. Discovery An ancient Egyptian calendar of lucky and unlucky days composed some 3,200 years ago may be the oldest preserved historical document of the discovery of a variable star, the eclipsing binary Algol. Of the modern astronomers, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heliometer
A heliometer (from Greek ἥλιος ''hḗlios'' "sun" and ''measure'') is an instrument originally designed for measuring the variation of the sun's diameter at different seasons of the year, but applied now to the modern form of the instrument which is capable of much wider use. The basic concept is to introduce a split element into a telescope's optical path so as to produce a double image. If one element is moved using a screw micrometer, precise angle measurements can be made. The simplest arrangement is to split the object lens in half, with one half fixed and the other attached to the micrometer screw and slid along the cut diameter. To measure the diameter of the sun, for example, the micrometer is first adjusted so that the two images of the solar disk coincide (the "zero" position where the split elements form essentially a single element). The micrometer is then adjusted so that diametrically opposite sides of the two images of the solar disk just touch each other. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Napoleonic Wars
The Napoleonic Wars (1803–1815) were a series of major global conflicts pitting the French Empire and its allies, led by Napoleon I, against a fluctuating array of European states formed into various coalitions. It produced a period of French domination over most of continental Europe. The wars stemmed from the unresolved disputes associated with the French Revolution and the French Revolutionary Wars consisting of the War of the First Coalition (1792–1797) and the War of the Second Coalition (1798–1802). The Napoleonic Wars are often described as five conflicts, each termed after the coalition that fought Napoleon: the Third Coalition (1803–1806), the Fourth (1806–1807), the Fifth (1809), the Sixth (1813–1814), and the Seventh (1815) plus the Peninsular War (1807–1814) and the French invasion of Russia (1812). Napoleon, upon ascending to First Consul of France in 1799, had inherited a republic in chaos; he subsequently created a state with stable financ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Battle Of Jena–Auerstedt
The twin battles of Jena and Auerstedt (; older spelling: ''Auerstädt'') were fought on 14 October 1806 on the plateau west of the river Saale in today's Germany, between the forces of Napoleon I of France and Frederick William III of Prussia. The defeat suffered by the Prussian Army subjugated the Kingdom of Prussia to the French Empire until the Sixth Coalition was formed in 1813. Several figures who were later integral to the reformation of the Prussian Army participated at Jena–Auerstedt, including Gebhard von Blücher, Carl von Clausewitz, August Neidhardt von Gneisenau, Gerhard von Scharnhorst, and Hermann von Boyen. Background Following the Prussian declaration of war, Napoleon initiated his campaign against the Fourth Coalition by thrusting a 180,000-strong force through the Frankenwald. The Prussian army, meanwhile, awaited Napoleon's advance with a force composed of about 130,000 Prussians and 20,000 Saxons. The Prussians were not organized well enoug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frederick William IV Of Prussia
Frederick William IV (german: Friedrich Wilhelm IV.; 15 October 17952 January 1861), the eldest son and successor of Frederick William III of Prussia, reigned as King of Prussia from 7 June 1840 to his death on 2 January 1861. Also referred to as the " romanticist on the throne", he is best remembered for the many buildings he had constructed in Berlin and Potsdam as well as for the completion of the Gothic Cologne Cathedral. In politics, he was a conservative, who initially pursued a moderate policy of easing press censorship and reconciling with the Catholic population of the kingdom. During the German revolutions of 1848–1849, he at first accommodated the revolutionaries but rejected the title of Emperor of the Germans offered by the Frankfurt Parliament in 1849, believing that Parliament did not have the right to make such an offer. He used military force to crush the revolutionaries throughout the German Confederation. From 1849 onward he converted Prussia into a cons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Bonn
The Rhenish Friedrich Wilhelm University of Bonn (german: Rheinische Friedrich-Wilhelms-Universität Bonn) is a public research university located in Bonn, North Rhine-Westphalia, Germany. It was founded in its present form as the ( en, Rhine University) on 18 October 1818 by Frederick William III, as the linear successor of the ( en, Academy of the Prince-elector of Cologne) which was founded in 1777. The University of Bonn offers many undergraduate and graduate programs in a range of subjects and has 544 professors. The University of Bonn is a member of the German U15 association of major research-intensive universities in Germany and has the title of "University of Excellence" under the German Universities Excellence Initiative; it is consistently ranked amongst the best German universities in the world rankings and is one of the most research intensive universities in Germany. Bonn has 6 Clusters of Excellence, the most of any German university; the Hausdorff Center fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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